Performance of interface hoses for thermal conditioning system of "Cyclon-4" space rocket in extreme conditions

Abstract

This article contains the analysis of the performance of interface hoses for the thermal conditioning system of a Cyclone-4 space rocket in extreme operating conditions. thermal conditioning system interfaces with rubber hoses must ensure a tightness of a hose at a rocket’s inlet with easy detachment, involving little to no force impact on the rocket during its start on its one end, and rigid connection with a pipeline of the thermal conditioning system ground part, ensuring the hose tightness and retaining after the launch of a rocket on its other end, under any abnormal operating conditions. As it is shown in the article, this goal is attained by inducing contact stresses on surfaces adjacent to the rubber hose, originating from a designed radial compressive stress and coarseness of the contact surfaces. At the same time, the detachable part is subjected to lower radial deformation than the fixed one.        To prevent any operating pressure excess in the thermal conditioning system ground part that might lead to extreme operating conditions, the retaining and release mechanism has been designed in such a way that under the operating conditions of pressing the hose’s sealing part, a proper stable gap would be ensured between the external radius of the rocket’s inlet protrusion and the internal diameter of its rim, so that the hose's sealing part could act as a safety valve. In such case, upon an excess of the permissible operating pressure, the hose’s sealing part would protrude through the gap mentioned by expanding and getting thinner, thus leading to detachment of the hose from the rocket’s inlet in the course of its launch or launch abort.        In case of the retaining and release mechanism’s pin failure, the thermal conditioning system interface design would ensure the guaranteed failsafe detachment of the thermal conditioning system hoses with minimum stress on both the rocket and the thermal conditioning system ground part. As in a case of a critical pressure excess in the thermal conditioning system, the hose’s sealing part would act as a safety valve thanks to its axial extension under stresses from the rocket’s launch, the transportation and erection installation’s boom movement, or both factors at the same time. The hose’s sealing part, having a smaller cross-section in the area of the groove for retaining and release mechanism, would shrink in thickness during stretching and expand through the gap between the outer diameter of the rocket’s inlet protrusion and the internal diameter of the retaining and release mechanism’s rim, which was proven experimentally on a special test bench simulating operating conditions close to the real ones. At the same time, the stresses of the hose detachment from the rocket’s inlet are less than the hose’s rupture stresses in the axial direction by several orders during stretching.